article: A teacher stood in front of his history class of twenty students just before handing out the final exam. His students sat quietly and waited for him to speak.
  "It's been a pleasure teaching you this term," he said. "You've all worked very hard, so I have a pleasant surprise for you. Everyone who chooses not to take the final exam will get a 'B' for the course."
  Most of the students jumped out of their seats. They thanked the teacher happily, and walked out of the classroom. Only a few students stayed. The teacher looked at them. "This is your last chance," he said. "Does anyone else want to leave?" All the students there stayed in their seats and took out their pencils.
  The teacher smiled. "Congratulations  ," he said. "I'm glad to see you believe in yourselves. You all get A."
question: This story most probably took place  _  .
options: at the beginning of the term in the middle of the term at the end of the term at the beginning of the school year